U.S. Pat. No. 2,285,616 discloses an actuating unit of a motor vehicle seat. In this case, the base part is formed as a beam which is rigidly connected to the seat rail. The actuating element is a locking lever comprising a locking member engaging into a latching strip connected in the floor rail. A pivot axis is disposed parallel to the longitudinal adjustment direction of the rails, it reaches through bearing openings of the base part and the actuating element. Finally, a spring is provided, which is fitted onto the pivot axis, is supported by the base part on the one hand and by the actuating element on the other hand, and which elastically biases the actuating element into a rest position relative to the base part, wherein this rest position is the engaging position into the latching strip.
Such actuating units have proved themselves in principle; they have been used for a long time. Nevertheless, they have drawbacks. For example, the installation effort is considerable. Though the pivot axis is easy to install, it must, however, be secured against axial movement by additional means. Additional room is required on the pivot axis for accommodating the spring. The spring must be hooked in separately after it has been pushed onto the pivot axis. The known actuating unit has many separate parts.